During processing and transfer, molten metal such as aluminum, aluminum alloys and others are typically handled and/or contained in various devices, vessels, troughs, launders and other containment and movement/transfer devices. Molten metal troughs for example are commonly used to transfer and contain molten metal.
While the molten metal contains a significant amount of internal heat, in many applications it is desirable and/or necessary to provide additional or supplemental heat to the molten metal in the handling devices in order to maintain the desired temperature of the molten metal and/or reduce the temperature differential from the center of the molten metal to the molten metal interface within the handling device. Supplemental or additional heat can supply heat to and through the refractory of the handling or containment device, and to the molten metal itself.
In some applications if the addition of the heat to the molten metal is not sufficiently controlled, the industry has experienced hot spots on the interior surface of the metal handling device (such as a trough) which can cause undesirable issues in the molten metal and on the interior surface of the refractory of the handling device. The balancing interest and concern is that the more the heat supply is reduced or buffered to avoid creating hot spots, generally the less energy efficient the process is.
Past attempts to address this situation have included creating continuous air gaps between the heater element and the refractory body of the handling device; using an expensive higher grade of material that makes the product potentially cost prohibitive; and others.
It is also desirable in some embodiments of this invention to maximize the conduction of heat, versus convection, radiation and/or emissive heat transfer across air or other gaps, which tends to increase the energy efficiency when a conductive or highly conductive material is used for said conduction. In some cases it is the configuration of the components of the system that results in said efficiencies, and in others the mechanical application of forces may be imparted to the various components to minimize the formation of gaps due to dissimilar expansion and contraction of adjacent materials, i.e. to squeeze or keep them squeezed together.
It is an object of some embodiments of this invention to provide a molten metal handling, containment and/or heating device that efficiently and effectively distributes the heat supplied to the molten metal while avoiding the creation of hot spots and other related issues.
It is a further objective of some embodiments of this invention to provide such a molten metal handling and heating device that provides sufficient desired heat through the bottom and/or side walls of the refractory body that a top to the device is not required.
It is also an objective of some embodiments of this invention to maximize the thermal or heat transfer by conduction or conductive heat transfer.
Other objects, features, and advantages of this invention will appear from the specification, claims, and accompanying drawings which form a part hereof. In carrying out the objects of this invention, it is to be understood that its essential features are susceptible to change in design and structural arrangement, with only one practical and preferred embodiment being illustrated in the accompanying drawings, as required.